For everything account/serial code related, you need to contact Customer Support.
They can be found here: https://help.ea.com/contact-us
You have the option to contact them by mail, phone or Live Chat. Make sure you have a game, a category and a platform selected for the options to become available.
If the Live Chat option is not active for you, choose US as your country.
I don't work or have any association with EA. I give advice to the best of my knowledge and cannot be held responsible for any damage done to your computer/game.
Please only contact me via PM when asked to do so.